Abstract

Farmer-supplied subjective ratings of cows milking speed, scored in 5 categories as 'very fast', 'fast', 'average', 'slow' or 'very slow' were analyzed. Scores were affected by herd- year- season of calving, age at calving and stage of lactation when scored but not by test day milk yield. Heritability estimates were 0.21 and 0.14 for scores up to day 110 of lactation for Canadian Holsteins and Ayrshires, respectively, and 0.17 and 0.16 for scores at the end of lactation. The estimate of repeatability of scores for the same cow in different lactations was 0.42 for Holsteins and 0.37 in Ayrishires.